Method for deburring components of considerable length



April 1 96 M. M. GUIBERT ETAL 3, 7

METHOD FOR DEBURRING COMPONENTS OF CONSIDERABLE LENGTH Filed March 5,1963 2 Sheet S-Sheet 1 55 114466 c'A rang; TAN/(5' BUCKET can/r5702 ellE Marak 4 GEAR/N6 Apr l 1964 M. M. GUIBERT ETAL 3,128,577

METHOD FOR DEBURRING COMPONENTS OF CONSIDERABLE LENGTH Filed March 5,1963 2 Sheets-Sheet 2 CRANK 2.?

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MART/N M. 60185T United States Patent Ofiice 3,128,577 Patented Apr. 14,1964 3,128,577 METHGD 230R DEhURRlNG COMPONENTS OF GNHDERABLE LENGTHMartin M. Guibert, Port Orchard, and Curtis S. Skinner, Jr., Renton,Wash, ,assignors to The Boeing Company, Seattle, Wash, a corporation ofDelaware Filed Mar. 5, 1963, Ser. No. 262,894 11 Claims. (Cl. 51-7) Thisinvention relates to a method of debnrring and surface improving, andmore particularly to a method for removing burrs caused by machining,generating a small r-adius where the burrs were, and improving themachined surface by removing cutter marks.

In the past years many attempts to devise an economical method ofdeburring spar details and other long, straight components have beenmade by machine builders and companies associated with the airframeindustry. These methods have included deburring with chemicals,deburring in a vibrating tank of abrasive media, deburring byreciprocating the workpiece in a tank of abrasive media, deburring b'yelectrochemical deplating, and deburring by abrasive blasting. All ofthe above stated prior methods proved unsatisfactory for productionexcept the method of reciprocating a workpiece submerged in a bed ofab-rasive media that was fluidized by vibration. While this method waseconomical and produced excellent results, the maximum workpiece lengthwas limited by the size of the abrasive bed. Since spars utilized in theairframe industry range to a length of 55 feet, the above method ofreciprocating a spar of that length in a bed of abrasive media waseconomically prohibited due to the length of the bed required therefor.

The instant invention overcomes the objections of each of the abovestated prior deburring methods by providing a method which provides thefollowing, features:

(1) A tank of abrasive media fluidized by vibration;

(2) A means of feeding the workpiece through the media;

(3) A system of retaining the media while feeding through the workpiece;and

(4) A method of reciprocating the workpiece longitudinally While it isbeing fed through the media.

Therefore, it is an object of this invention to provide an economicalmethod of deburring, descaling, or surface finishing of elements ofconsiderable length.

It is a further object of the invention to provide a method or deburringelements in a fluidized bed of abrasive media by continuous feed throughand reciprocation of the elements at a predetermined rate.

Another object of the invention provides a method of deburring, byreciprocating action, a spar or other similar components, in a slurry ofabrasive media while continuously feeding through the spar.

Other objects of the invention not specifically set forth above willbecome readily apparent from the accompanying description and drawingsin which:

FIG. 1 is a diagrammatic view of an embodiment of the apparatus forcarrying out the invention with certain elements being cut away oromitted for clarity;

FIG. 2 is a perspective view of one of the sealing means of theinvention;

FIG. 3 shows in detail the drive mechanism of the FIG. 1 apparatus; and

FIG. 4 shows in detail an embodiment of the inertia retarder means forthe feed mechanism of the FIG. 1 apparatus.

FIG. 1 shows a housing 1 having support mechanism 2, said housing beingdivided into three compartments, the two end compartments constitutingspillage catch-tanks 3, the center compartment 4 constituting a tank forthe abrasive media 5. Each of the walls of the center compartment 4 isprovided with aligned sealing means 6 to permit the passage of workpieceor spar 7 therethrough, the details of sealing means '6 being describedhereinafter. Each of the outer walls of compartments 3 can be providedwith sealing means such as sealing means 6 of compartment 4 to provideadditional sealing if dmired. However, such additional sealing is notnecessary. In operation abrasive media 5 completely surrounds spar 7 buthas been here shown below the spar [for clarity.

Powered feed rolls 8, which are in this instance Adiprene covered, aremounted on reciprocating arm mechanism 9 and feed spar 7 through housing1, media 5 and sealing means 6 at a predetermined speed. While not showncompletely, identical reciprocating arm mechanism 9 and rfeed rolls 8are positioned on the left side of housing '1. Reciprocating armmechanisms 9 are synchronized by interconnecting bar means 10 :anddriven via pitman 11 by drive motor and gearing mechanism 12, shown indetail in FIG. 3.

The lower feed rolls '8 are powered by motor and gearing mechanism 12via chain or belt and pulley means generally indicated at 13. The upperfeed rolls are driven by coupling means 14, for example, universaljoints connected with the drive means 13. All of the feed rolls 8 aredriven in synchronization. Positioned on each of arm mechanisms 9 isfeed roll pressure adjustment mechanism 15.

Bucket conveyor means 16 is operatively positioned in each of spillagecatch-tanks 3- (only one con eyor being shown) to return the media 5which has spilled through sealing means 6 to the center compartment 4.The drive (not shown) for conveyor means 16 can be powered from chainand pulley means 13 or can be driven by a separate mot-or if desired.

As shown in FIG. 2, sealing means 6 comprises a frame 17 tor holdinginterleafed strips generally indicated at 18 of flexible material suchas rubber and sheet metal such as aluminum. Strips 18 are adjusted tothe configuration of the workpiece or spar 7 and are held in place bythumb screws 19 which are screw threaded through frame 17 to pressblocks 20 against the strips 18 thus permitting the workpiece to passthrough with a minimum of spillage of media 5.

The drive motor and gear mechanism 12 as shown in FIG. 3 comprises anelectric motor 21 driven by any available source of power, a power traingenerally indicated at 22 interconnects the output shaft of motor 21with a crank 23 which drives pitman 11 for driving reciprocating armmechanisms 9. Power train 22 includes ling gear and pinion means 24which powers chain and pulley means 13 for driving feed rolls 8.

FIG. 4 shows inertia retarder means for reciprocating arm mechanisms 9to cushion the shock load at the stroke reversal point, and to assist inovercoming inertia at the start of the stroke in the opposite direction.The inertia retarder means comprises a bumper plate 25 positioned underhousing 1 and rigidly attached to support mechanism 2. Interconnectingbar means 10 passes through the upper portion of bumper plate 25.Positioned on bar 10' on each side of bumper plate 25 in opposedrelationship are recoil and booster spring means 26, spring means 26being adjustably located on bar 10' by means 27 whereby the position ofthe spring means may be adjusted in accordance with the desired lengthof stroke of arm mechanisms 9.

Also shown in FIG. 4 are the vibrators to fiuidize the media 5 whichconsist of air powered vibrators 28 attached to the bottom of the mediatank (center compartment) 4 and connected with an air supply source byconduit means and controls as generally indicated at 29.

Fluidization of media 5 serves the following functions:

( 1) It lessens the resistance to the spars passing through;

(2) It causes the media to move constantly, thereby presenting freshabrasive to the workpiece on a continuous basis. This expedites metalremoval and prevents the media from loading and glazing;

(3) It rotates the mass of media vertically in the tank, therebycarrying a cleaning compound and water solution from the bottom of thetank to the Work area; and

(4) It aids, to a limited extent, the deburring and surface improvingaction of the process.

Though not shown in the instant embodiment of the apparatus, the mediais supported by a sheet metal plate, located approximately 6 inchesabove the bottom of tank 4. The void beneath the plate and a portion ofthe media area in the tank is filled with a water and cleaning compoundsolution. The solution filled area below the plate serves the dualpurposes of lessening the weight to be vibrated by reducing the mediaload, and of dispersing the vibration (induced at two spots on the tankbottom) evenly beneath the plate. The solution in the media functionsfor cleaning the media during debut-ring.

While the instant embodiment of the apparatus utilizes air poweredvibrators, mechanical vibrators are also efficient for mediafluidization and can be utilized on the apparatus, desired.

While not shown, the apparatus includes a solution filtering andrecirculating system feeding into the abrasive media.

Also, two sets of feed rolls can be mounted on each of the reciprocatingarms. The rolls would be mounted in pairs with the axes at 90 degrees tofacilitate grasping the workpiece by the sides, or at the top andbottom. All rolls would be driven in synchronization as in the instantembodiment.

The following example is set forth to show the advantages of theinvention under actual work conditions and to set forth its effectiverange of operation:

Media tank length: 4 foot Workpiece length: 12 foot Contants:

(1) Media-bonded aluminum oxide triangles, Size No. 2. (2) Mediaweightl06 pounds/cubic foot. (3) Total media in tank at maximumdepth2880 cubic inches. (4) Total workpiece and media contact area576sq. inches. (5) Vibration-4300 cycles per minute. (6) Vibrationamplitude0.015 inch. (7) Feed roll pressure on workpiece-484 pounds. (8)Media pressure/square inch/inch hei-ght--0.0709

pound. Variables:

(1) Media height above top of workpiece-2 to 5 /2 inches. (2)Reciprocation-65 to 130 stroke cycles/minute. -(3) Stroke length-4) to2% inches.

(4) Feed rate-6 inches to 2% feet/minute.

The parts in this example were machined T section aluminum spar details.This con-figuration, because of the thin leg, oifered a minimum contactarea to the feed rolls, thus reducing the gripping capability of therolls due to the narrow area of the workpiece and thereby providing themost severe feed conditions of any spar type.

Tests were conducted under the various combinations possible with theconditions above. Parts were fed through singly, and with one partfastened end to end with another.

While the method of the invention performed satisfactory under all ofthe conditions tested, the best combination of variables developed was:

(1) Reciprocation130 stroke cycles/minute i (2) Media height above topof workpiece-5 /2 inches. (3) Stroke length2 inches. (4) Feed rate2%feet/minute.

Under the conditions set forth directly above the parts were completelydeburred, and the design-required corner radii of 0.008 to 0.010 inchdeveloped. The deburring rate of 2% feet/minute was approximately fivetimes that of manual deburring which was the only prior known method ofdeburring parts of considerable length.

The following are features which are incorporated into the deburringapparatus for carrying out the instant invention:

(1) Sets of synchronized feed rolls to facilitate grasping the workpieceand feeding it through the abrasive media.

(2) A vibratory system, with variable controls for both amplitude andfrequency,

(3) A solution filtering and recirculating system for cleaning themedia.

(4) A media tank with the maximum length compatible with the shortestpart planned for this process. The tank contains 6 inches of media belowthe workpiece, and 6 inches beyond the widest part planned forprocessing in the machine. The interior of the tank is designed tocontain no square corners or pockets capable of causing media retentionand packing at the entrance and exit ends.

(5) A quick-detach means of installing and removing the door sealretainers, the door seals being flush with the interior of the mediatank.

(6) The media tank floated on springs or air cushions similar toconventional vibratory tubs.

(7) The feed rate variable from 2 to 15 feet per minute.

(8) The reciprocation rate variable from 65 to 300 stroke cycles perminute.

(9) Media flow under vibration in a circular lateral pattern with nolongitudinal media flow in the tank.

The instant invention has thus provided a method which has fulfilled thevast need both in the airframe industry and in other manufacturingoperations dealing with long, straight line components that requiredeburring, descaling, or surface finishing.

Although a particular embodiment of the apparatus for carrying out theinvention has been illustrated and described, it will be obvious tothose skilled in the art that various changes and modifications may bemade without departing from the invention, and it is intended to coverin the appended claims all such changes and modifications that comewithin the true spirit and scope of the invention.

What We claim is:

1. A method of de'burring, descaling or surface finishing partsincluding the steps of: containing a predetermined quantity of abrasivemedia, controllably vibrating the abrasive media for providing acircular flow pattern thereof, passing a part through the abrasive mediaat a predetermined rate, and controllably reciprocating the part duringpassage through the abrasive media.

2. The method defined in claim 1 wherein the abrasive media surroundsthe part by at least 5 inches.

3. The method defined in claim 1 wherein the rate at which the part ispassed through the media is in the range between 6 inches to 15 feet perminute.

4. The method defined in claim 1 wherein the step of controllablyvibrating the abrasive media includes independently controlling thefrequency and amplitude of the vibration.

5. The method defined in claim 1 wherein the part is reciprocated in therange between 65 to 300 stroke cycles per minute with a stroke length inthe range between 0 .1 to 2% inches.

6. The method defined in claim 2 wherein the rate at which the part ispassed through the media is in the range between 6 inches to 15 feet perminute.

7. The method defined in claim 6 wherein the step of contro lablyvibrating the abrasive media includes ind 6 pendently controlling theamplitude and frequency of References Cited in the file of this patentthe vibration.

8. The method defined in claim 7 wherein the part is UNITED STTESPATENTS Ieciprocated in the range between 65 to 300 stroke cycles21159540 Mwolamhw May 1939 per minute with a stroke length in the range.between 5 2,218,353 Gruenberg 1940 (11 to inches 2,621,446 Russell Dec.16, 1952 9. The method defined in claim 1 with the additional 2,664,676CuPPers 1954 steps of filtering and recirculating solution for the abra-216841562 Balz et July 271 1954 Sive media 2,686,991 Powell et a1 Aug.24, 1954 10. The method defined in claim 1 wherein the vibrat- 1021,733,563 Kafier 7, 1956 ing media has a circular lateral flow pattern.2,746,709 M 9 May 1956 11. A method of deburring, descaling or surfacefinish- 2,883,809 slmllam P 1959 ing parts including the steps of:containing a predeter- 2,897,633 Buhr 1959 mined quantity of abrasivemedia, controllably vibrating 2,921,413 y Ian 1962 the abrasive mediafor providing a fluidized bed thereof, 15 E2 M 3 passing a part Withinand through the fluidized bed of abrasive media at a predetermined rate,and controllably, reciprocating the part during passage through theabrasive media.

1. A METHOD OF DEBURRING, DESCALING OR SURFACE FINISHING PARTS INCLUDINGTHE STEPS OF: CONTAINING A PREDETERMINED QUANTITY OF ABRASIVE MEDIA,CONTROLLABLY VIBRATING THE ABRASIVE MEDIA FOR PROVIDING A CIRCULAR FLOWPATTERN THEREOF, PASSING A PART THROUGH THE ABRASIVE MEDIA AT APREDETERMINED RATE, AND CONTROLLABLY RECIPROCATING THE PART DURINGPASSAGE THROUGH THE ABRASIVE MEDIA.